The present invention relates generally to accessory mounting assemblies for combat weapons such as the modular integrated accessory systems found on most modern combat weapons. More specifically, the present invention relates to an accessory mounting assembly that includes a buffer pad to prevent damage to the rail when the mounting assembly is engaged therewith, while also including a means for reliably retracting the buffer pad to facilitate dismounting when the mounting assembly is disengaged.
As the field of combat and commercial weaponry expands, numerous add-on enhancements have become available for attachment to standard firearms, thereby significantly upgrading the capability of the firearm. Of particular interest in the area of combat weapons is the well-known M16/M4 weapon system (M16 and M4 are trademarks of Colt Defense, Inc.). The M16 has been in service for a number of years and will continue to be a popular rifle both in U.S. and foreign militaries for the foreseeable future. Generally, the M16/M4 weapon 2, as depicted in FIG. 1, includes a lower receiver 4, upper receiver 6, butt stock 8, and barrel 10.
The newer models of the M16/M4 weapons further include a mil-std 1913 dovetail rail 12 extending along the top of the upper receiver. This integrated receiver rail 12 provides a convenient mounting point for many types of enhancement devices such as scopes and other sighting devices. However, space on the upper receiver rail 12 is limited, and many military personnel often have multiple sighting devices that are each tailored to perform in different combat situations. In addition, there are a variety of lighting devices, handgrips, etc. that could also be attached to the weapon for enhanced use of the weapon. The difficulty is that there is simply not enough space on the integrated rail provided on the upper receiver to accommodate all of the desired accessories. Accordingly, the increasing development and refinement of laser sights, infrared lighting, visible lighting, night vision, and specialized scopes and magnifiers, and other accessories continues to drive the need for versatile and reliable integration systems that include additional mil-std 1913 dovetail rails positioned above or around the barrel of the weapon that can support this important equipment and yet stand the test of rugged military use and abuse.
Responding to this need, the applicant has developed a modular integrated rail system (A.R.M.S.® S.I.R.® system), which has been well received by the military and has become popular with several branches of the military (See FIG. 2). The A.R.M.S. S.I.R. system is fully described in U.S. Pat. No. 6,490,822, the entire contents of which are incorporated herein by reference. These modular integrated rail systems for combat weapons 2 generally include an upper hand guard 14, a means 16 for securing the upper hand guard 14 to the weapon 2, a lower firearm accessory 18 (in most cases this is a lower hand guard), various optional rail segments, and in many cases, a sling swivel 20 for attaching a shoulder sling to carry the weapon 2.
The upper hand guard 14 is the main structural element of the system. The upper hand guard is 14 generally semi-cylindrical in shape and has a forward end and a rearward end and a mil-std 1913 dovetail rail 22 extending longitudinally between the forward end and the rearward end. The semi-cylindrical upper hand guard 14 further includes symmetrically opposing side walls that extend outwardly and downwardly from the dovetail rail and terminate in symmetrically opposing longitudinally extending mounting channels. The mounting channels are used to mount various accessories, such as a lower hand guard 18 or a grenade launcher, to the upper hand guard 14.
An interface means 16 is provided at the rearward end of the upper hand guard 14 to removably secure the upper hand guard 14 to the firearm 2. In the original S.I.R. system as shown in U.S. Pat. No. 6,490,822, the clamp is an elongated clamping rail that secures the upper hand guard 14 to the dovetail rail 12 on the top of the upper receiver 6 of the weapon 2. In the newer S.I.R. systems, the interface means is a U-shaped yoke or clamp that secures the upper hand guard 14 to the barrel nut.
As is well known in this area, field modification of weapons is critical in combat situations. For example, it may be desired to swap the lower hand guard for a grenade launcher, which can be attached to the upper hand guard, or to add an optional rail segment for securing an added accessory. Similarly, there may be a desire to exchange various different sights or lighting accessories that are mounted on the various dovetail rails positioned around the weapon. In this regard standardized accessory mounting assemblies have been developed to allow quick and easy removal and mounting of these devices relative to the dovetail rails.
The difficulty with the prior art mounting assemblies is that the clamping surfaces that engage with the dovetail rail are necessarily formed from steel while the Weaver interfaces, receiver sleeves and upper receivers are generally made of aluminum or other light weight material. Since these materials are softer than the steel used for the clamping surface, over time and after repeated use, the operation of the clamping foot scratches, cuts and erodes the underlying rail interface.
To overcome the difficulties associated with the wear between the dissimilar metal surfaces, the applicant further developed a rugged mounting assembly that includes a buffer pad 24 disposed between the clamping surface 26 of the mounting assembly 28 and the rail interface 22 (See FIGS. 3A and 3B) that enhances the ability to fasten accessories onto the SIR system as is shown and described for example in U.S. Pat. No. 5,276,988, the entire contents of which are incorporated herein by reference.
However, the inclusion of a buffer pad itself has also introduced a new set of difficulties in that when the mounting assembly is disengaged and the clamping foot is retracted, the buffer pad often remains in a downwardly depending position as can best be seen in FIG. 3B. As a result, when installing a mounting assembly that includes a buffer pad, the device must be tilted in such a manner that the buffer pad is cleared out of the way, otherwise it interferes with installation of the mounting assembly onto the rail interface.
Accordingly, there is a need for a mounting assembly that allows for the releasable mounting of various accessories onto the standard dovetail rail found on modern combat weapons. Further, there is a need for a mounting assembly that includes the beneficial features found in the prior art throw while also including a reliable means for retracting the buffer pad in a manner that facilitates installation and removal of the device relative to an S.I.R. system or other interface rail mount.